Range hoods are used above cooking surfaces to remove grease, common odors and hazardous gases created during the cooking process. Typically, range hoods have a pair of motors horizontally installed in a motor housing within the hood body. Each motor drives a fan. The fans suck air from the cooking area below and force it through the motor housing to ventilation piping.
As the vaporized grease contained in the entrained air travels through the motor housing, some of it condenses on the inside walls of the housing from where the shaping of the walls and floor of the housing directs the grease to a circular grease catcher mounted below each fan opening. Grease catchers are known in the art as illustrated in U.S. Pat. Nos. 6,216,686 B1 and 5,537,988.
Grease catchers are also adapted to capture any grease that drips off the fan blades when the motors are turned off. Typically, the grease catcher has radial inner and outer trays with a wall separating them. The wall extends vertically so as to be almost flush with the lower edge of the outer circumference of the fan. In this way air being drawn in by the fans is compelled to enter the motor housing rather than the hood body. The wall therefore acts to control the air currents of the range hood.
The grease catchers are usually provided with an inclined base or floor, so as to direct accumulated grease to a hole in the floor. A hose is attached to the hole to convey the grease to a grease receptacle outside the range hood.
The motor housing and grease catchers are mounted within the hood body. Openings in the lower surface of the hood body are positioned so as to match those of the motor housing. Typically the lower surface of the hood body is removably fitted into the main hood body. A protective grill is attached to the outside of each opening in the hood body so as to prevent the insertion of body parts when the fan is in operation.
Alternatively, as set out in my U.S. and Canadian patent applications, numbers Ser. No. 10/035,116 and 2,365,790 respectively, the motor housing may be adapted to act as a grease catcher itself. In this system, a circular wall defining the motor housing intake openings projects vertically into the motor housing, acting as a barrier to grease accumulated therein. The accumulated grease drains directly from the housing rather than to a grease catcher. Grease trays inserted into the intake openings provide a barrier for proper airflow into the housing and to capture any grease that should happen to drip from the fan when it has stopped motion.
Both of the foregoing designs rely on gravity to cause the accumulated grease to drain out of the range hood. However, gravity is not effective in removing all the grease with the result that some becomes caked on to the interior surfaces, thereby reducing the efficiency of the range hood and creating a possible fire hazard.
The foregoing systems of motor housing and grease catchers therefore require periodic cleaning to remove condensed grease accumulated on the fans, motor housing interior and grease trays. In order to clean the interior of the range hood, a user must first remove the lower surface of the hood body, following which the grease catcher must then be removed. This can be quite awkward and is difficult for those without the strength to support the weight of the lower surface. Washing the inside of the motor housing, the fans and the grease trays to remove the accumulated grease is also time consuming.
Attempts have been made to overcome the necessity to manually clean the interior of a range hood exhaust system. It is known in the art to provide a washing fluid under pressure in order to clean the interior of the exhaust system. For example, U.S. Pat. No. 4,259,945 teaches an exhaust system in which a washing fluid under pressure is used to clean the flue and fan. Similar washing fluid systems are taught in U.S. Pat. Nos. 3,795,181 and 4,085,735.
A similar approach is known in the art with respect to the range hood design described above. A fluid delivering nozzle is fitted into a hole in the side of the motor housing so as to deliver a spray of washing fluid to clean the interior. This is done while the motors are activated so that the force of the air being drawn into the motor housing forces the sprayed fluid against the interior surfaces of the motor housing and prevents any liquid from passing through the air intakes.
While these prior art systems reduce the amount of cleaning required of the exhaust system, maintenance is still required. Because there is so much waste fluid resulting from the combination of the grease and the washing solution, a large waste fluid receptacle is required and must be emptied often. The waste receptacle takes up usable space below the range hood and is not pleasing to the eye. In addition, the washing fluid receptacle must be constantly refilled.
It is therefore an object of an embodiment of the present invention to provide a range hood in which the interior of the range hood, including the motor housing and the fans, may be automatically cleaned without the use of washing fluid so as to negate the need for a large waste fluid receptacle or the constant refilling of a washing fluid receptacle.
Various aspects of the invention address these objects, but not all aspects of the invention necessarily address all such objects simultaneously. Other objects of the invention will be apparent from the description that follows.